Effects of the residual ammonium concentration on NOB repression during partial nitritation with granular sludge.
Effects of the residual ammonium concentration on NOB repression during partial nitritation with granular sludge.
复制标题
DOI：
10.1016/j.watres.2016.10.028
复制
发表时间：
2016-12
期刊：
影响因子：
12.8
通讯作者：
Vincent Poot;M. Hoekstra;Mitchell Geleijnse;M. V. van Loosdrecht;Julio Pérez
中科院分区：
文献类型：
--
作者：
Vincent Poot;M. Hoekstra;Mitchell Geleijnse;M. V. van Loosdrecht;Julio Pérez
在含有颗粒污泥的小试气升式反应器(1.5L)中稳定地实现了部分亚硝化。在20℃下连续运行处理低浓度合成废水(50 mg·N-NH_4~+/L，无化学需氧量)，在部分亚硝化过程中，氮负荷率可达0.8 mg·N-NH_4~+/(L·d)。在20℃下，当反应器中氨氮浓度低于2-5 mg·N-NH_4~+/L，DO浓度低于4 mg·O_2/L时，观察到了抑制亚硝酸盐氧化细菌(NOB)和促进NOB增殖的转换。在整个反应器运行过程中，被检测到是优势的NOB菌群，而亚硝化细菌则是。被发现随着时间的推移数量在增加。颗粒结构的层化，即氨氧化细菌(AOB)占据外壳，被发现在长期内对NOB的抑制非常重要。颗粒内的pH梯度在颗粒表面和颗粒中心之间包含约0.4的pH差，产生了向颗粒中心递减的氨梯度。较高的剩余氨氮浓度提高了距离颗粒表面较远的细胞的氨氧化速率，其中AOB和NOB之间的氧竞争更为重要，这有助于生物膜中两个种群的分层。
Partial nitritation was stably achieved in a bench-scale airlift reactor (1.5L) containing granular sludge. Continuous operation at 20 °C treating low-strength synthetic wastewater (50 mg N-NH4+/L and no COD) achieved nitrogen loading rates of 0.8 g N-NH4+/(L·d) during partial nitritation. The switch between nitrite-oxidizing bacteria (NOB) repression and NOB proliferation was observed when ammonium concentrations in the reactor were below 2–5 mg N-NH4+/L for DO concentrations lower than 4 mg O2/L at 20 °C.Nitrospiraspp. were detected to be the dominant NOB population during the entire reactor operation, whereasNitrobacterspp. were found to be increasing in numbers over time. Stratification of the granule structure, with ammonia-oxidizing bacteria (AOB) occupying the outer shell, was found to be highly important in the repression of NOB in the long term. The pH gradient in the granule, containing a pH difference of ca. 0.4 between the granule surface and the granule centre, creates a decreasing gradient of ammonia towards the centre of the granule. Higher residual ammonium concentration enhances the ammonium oxidation rate of those cells located further away from the granule surface, where the competition for oxygen between AOB and NOB is more important, and it contributes to the stratification of both populations in the biofilm.